Mechanism providing intermittent drive



Dec. 14, 1965 D. P. MCCURDY 3,223,205

MECHANISM PROVIDING INTERMITTENT DRIVE Filed May 31, 1963 5L ECTROMAWfT United States Patent 3,223,205 MECHANISM PROVIDING INTERMITTENT DRIVE Dudley P. McCurdy, York Harbor, Maine, assignor to General Electric Company, a corporation of New York Filed May 31, 1963, Ser. No. 284,685 1 Claim. (Cl. 18885) This invention relates to a driving mechanism and, more particularly, to a driving mechanism providing an intermittent drive.

In devices used in counting quantities of material, such as kilowatt hours, gallons, tons and the like, two types of driving mechanisms are generally used. In one type the driving mechanism is a continuous drive and is generally termed an analog driving means. The quantity to be counted is generally shown by a pointer which moves on a dial such as, for example, the standard kilowatt hour meter. The other type of drive is an intermittent drive and is generally called a digital drive. In this type of driving means the counted quantity is usually shown on a digital dial or counter which moves through ten positions which are numbered 0 through 9. These types of devices may be generally illustrated by the present-day gasoline pumps which use the digital dials to show both the gallons delivered and the cost of such gallons.

In many present day intermittent driving mechanisms various types of driving devices are used. In some, a motor is utilized and is energized intermittently by means of a counting pulse which indicates a single unit of the quantity to be counted. By means of gearing connected between the motor and a digital counter the digital counter will be rotated through a single count while the motor is energized. A second method which has been used to provide intermittent drive utilizes a pulse means indicative of a single unit of a quantity to be counted to actuate an electrical device such as an electromagnet, with the armature of the electromagnet operating on a ratchet type gear device to rotate a digital counter through a single count.

The above-discussed intermittent driving means have, in general, been considered unsatisfactory since a smooth operation of the counting dials could not be obtained. The driving force obtained through these types of intermittent driving is generally varied such as, for example, during the start up of the motor or of the ratchet device, thereby placing a varying stress on the gear train used in the operation of the counter. This has generally led to a requirement in such gear trains to provide more costly gears to prevent breakage and to ensure adequate life of the apparatus. A further problem in the above type of intermittent driving mechanism is the recurrent problem of overdriving of the digital counter. As will be understood, if the digital counter is driven beyond a particular digital indication, the digit dial will not be properly set at the desired figure. An accumulation of such overdrivings will result in an inaccurate count being indicated by the counting mechanism. From the above it will be apparent that there is presently a need in the field of intermittent driving to provide an intermittent driving means which provide for smooth operation of the counter and which will accurately count each unit of quantity measured and which may be made at a relatively low cost.

It is, therefore, one object of this invention to provide a new and improved intermittent driving mechanism.

A further object of this invention is to provide an intermittent driving mechanism of high accuracy utilizing low cost components.

A further object of this invention is to provide an inter- 3,223,205 Patented Dec. 14, 1965 mittent driving mechanism having substantially uniform stress on all driven parts.

A still further object of this invention is to provide an intermittent driving mechanism having an improved accuracy with desirably long life.

In carrying out this invention in one form a driving mechanism is provided comprising an electric motor connected to a digital counter mechanism for driving the same. A star wheel is provided interconnected with the motor and an escapement means is mounted adjacent the star wheel in blocking relation with such star wheel. Electromagnetic means are provided to move the escapement means into and out of blocking engagement with the star wheel. The electric motor is continuously energized and the electromagnetic means are energized by a pulse signal indicative of each count to be recorded by the counter. The escapement moves into and out of blocking engagement with the star wheel on energization of the electromagnetic means to allow the motor to rotate the counter for each unit of quantity to be counted.

The invention which it is desired to protect is particularly pointed out and distinctly claimed in the claims appended here-to. However, it is believed that this invention and its objects and advantages, as well as other obiects and advantages thereof, will be more clearly understood from the following detailed description of a preferred embodiment thereof, especially when considered in the light of the accompanying drawing, in which:

FIGURE 1 is a side view of a portion of a preferred form of intermittent driving means according to this invention;

FIGURE 2 is a top view of a preferred driving means taken on the line 2-2 of FIG. 1; and

FIGURE 3 is a top view of the star wheel and escapement device used in the preferred embodiment of this invention.

The invention set forth herein relates to an intermittent driving mechanism especially useful in digital counting devices. One form of counting device in which the intermittent driving mechanism of this invention finds utility is shown in patent application Serial No. 284,688, filed May 31, 1963 in the names of D. M. Ham and F. Serck-Han'ssen entitled, A Pulse Counting Device With Visual and Electrical Storage and Readout and which is assigned to the same assignee as this invention.

Reference will now be made to the drawing, in which like numerals are used to indicate like parts throughout the various views thereof, for a complete description of the presently preferred embodiment of this invention. However, it will be understood that such description is for illustrative purposes only, and that the invention is not limited thereto other than as indicated in the claims appended hereto.

Referring first to FIGS. 1 and 2 of the drawing there is shown a driving mechanism which comprises a motor 10, gear 12 and a gear 14. The gear 12 is mounted on the motor shaft 16 of the motor 10 and, therefore, rotates with the motor shaft 16 whenever motor 10 is energized. As will be understood, a friction or slipping clutch 13 may be provided on shaft 16, providing a slipping connection between motor 10 and gear 12, for intermittent driving of gear 12, in the manner described in the following portions of this description. The gear 12 meshes with the gear 14, fixedly mounted on a shaft 18, whereby the gear 14 and thus shaft 18 are driven by the motor 10 through gear 12. As will be understood, if a digital counter device is mounted on the shaft 18, such as is shown in the afore-mentioned application, then, as gear 14 is driven by motor 10, a digital counting device mounted on shaft 18 will be rotated. Obviously, such rotation would not provide accurate digital counting.

In order to provide a higher order count, the shaft 18 is provided with a transfer gear 20 which meshes, once every revolution of shaft 18, with the connecting gear 22. Connecting gear 22 is, in turn, meshed with gear member 24. As will be understood, gear member 24 is mounted on a shaft member 26 which may carry a digital counter means of a higher order than a digital counter on shaft 18. Thus, as will be understood, as a digital counter on shaft 18 makes one full revolution the transfer gear 20 meshing with the gear 22 will drive gear 24 to rotate the shaft 26 to provide a suflicient movement of a digital counter on such shaft to indicate a count of the next higher order.

If the motor 10 is continuously energized then the gear 12 will continuously rotate to thereby continuously rotate gear 14, which in turn will continuously rotate shaft 18. In order to provide the intermittent drive in the driving mechanism above discussed, a star wheel 28 is provided which is fixedly mounted on the shaft 18 so as to rotate therewith, As can be seen from FIGS. 2 and 3 of the drawing, the star wheel 28 is provided with five teeth 38, with each of the teeth being spaced 72 apart. An escapement mechanism 30 is also provided which is mounted on a shaft 32 adjacent to the star wheel 28, in the manner indicated in FIG. 3 of the drawing. As can be seen, the escapement mechanism 30 is provided with a pair of teeth 34 and 36 which may be moved into and out of blocking relation with one of the teeth 38 on the star wheel 28. As is shown in FIG. 3, the tooth 34 of the escapement 30 is in blocking engagement with a tooth 38 of the star wheel 28. If the escapement device 30 is now oscillated or rotated in a clockwise direction the tooth 34 will be moved out of engagement with the tooth 38 of the star wheel 28, thereby allowing the star wheel to rotate in a clockwise direction as indicated by the arrow. However, movement of the mechanism 30 in a clockwise direction will move tooth 36 of the escapement 30 into blocking relation with the star Wheel 28. Thus, as the star wheel rotates in a clockwise direction, another tooth 38 will contact tooth 36 of the escapement 30 thereby stopping movement of the star wheel 28. As will be evident from FIG. 3 of the drawing, the star wheel will rotate through only a 36 are as tooth 34 is moved out of blocking engagement with the star wheel and tooth 36 is moved into blocking engagement with the star wheel. From the relation set forth in FIGS. 1 and '2 of the drawing it will be obvious that as the star wheel rotates 36 it allows motor 10 to drive the shaft 18 through a 36 arc. As will be readily apparent, the driving of the shaft 18 through a 36 arc will allow the driving of any digital counter mounted on shaft 18 through one digit position.

From the above it will be evident that if the escapement device 30 is oscillated according to the counts to be counted into the counter that the driving mechanism disclosed will drive the shaft 18 through a single count for each movement of the escapement mechanism 30. In order to provide the desired movement of the escapement mechanism 30 a pair of electromagnets are provided, indicated at 40 and 42, and the adjacent sides of the escapement 30 are provided with armatures indicated at 44 and 46. As will be readily apparent from FIG. 3 of the drawing as the electromagnet 42 is energized it will attract the armature 46 on the escapement 30 thereby moving tooth 34 out of blocking engagement with the star wheel 28 and moving tooth 36 into blocking engagement with the star wheel 28. As the electromagnet 40 is energized it will attract armature 44 to oscillate the escapement 30 in a counterclockwise direction, thereby moving tooth 36 out of blocking relation and returning tooth 34 into blocking relation with the star Wheel 28. Thus, as will be readily apparent, the operation of the electromagnets 40 and 42 will oscillate the escapement device 30 so as to provide the driving of shaft 18 through a 36 angle for each energization of electromagnet 40 and electromagnet 42. As will be readily apparent to those skilled in the art, by alternately operating the electromagnets 40 and 42 through a contact device, whereby the electromagnets are alternately energized by each pulse indicative of a single unit of quanttity to be counted, the intermittent driving mechanism of this invention will operate to drive shaft 18 through a single, digital count for each pulse utilized for the energization of the electromagnets 40 and 42. For example, a contact device 50 as described in the afore-mentioned application Ser. No. 284,688 may be used to alternately energize the electromagnets 40 and 42. The use of contact device 50 is diagrammatically indicated in FIG. 3 of the drawing. Thus it will be apparent that the desired intermittent driving mechanism providing a smooth operation of the gear train of the counting device is provided and one in which a very accurate driving of the various elements of the gear train may be obtained. Thus it can be seen that the intermittent driving mechanism set forth herein obtains all of the objects and advantages hereinbefore set forth.

While the present preferred embodiment has been specifically described it will be readily apparent to those skilled in the art that various changes may be made. For example, it will be obvious that the star Wheel may be readily mounted on the shaft of the electric motor 10 rather than being mounted on the driven shaft 18, as is disclosed. Thus it will be apparent that many changes may be made without departing from the spirit and scope of the invention, as is defined in the appended claims.

What is claimed as new and which it is desired to secure by Letters Patent of the United States is:

A mechanism for providing intermittent drive, comprising, a star wheel adapted to be continuously driven, said star wheel having tooth members separated by substantially 72, an unitary escapement device having opposing tooth members, said opposing tooth members movable into and out of blocking relation with said tooth members on said star Wheel, a pair of opposed electromagnet means energizable by an electrical pulse, said opposed electromagnet means when energized operating on said escapement to move said opposing tooth members alternately into and out of blocking relation with said tooth members on said star wheel whereby said star wheel may be driven through an arc of substantially 36 before being blocked by one of said opposing tooth members.

References Cited by the Examiner UNITED STATES PATENTS 293,922 2/1884 Van Hoevenberg 188-85 1,200,822 10/ 1916 Erickson l8885 1,377,844 5/1921 McClutchen et al.

1,402,617 1/1922 Jordan 74-84 2,906,131 9/1959 Daugherty 74--84 FOREIGN PATENTS 610,897 12/1960 Canada.

MILTON BUCH-LER, Primary Examiner.

BROUGHTON G. DURHAM, ARTHUR L. LA POINT,

Examiners. 

